Gear-generating machine



NOV. 4, 1930. E FlNsEN A 1,780,350

GEAR GENERATING MACHINE` Filed Oct. l2, 1928 2 Sheets-Sheetk l 43 al@M', l

"0 9 INVENToR 44/ Egfz'fzdfaa 27 26 Fl ATTQQNEY y Nov. 4, 1930. E.FlNsl-:N

GEAR GENERATING MACHINE 2 Sheets-Sheet 2 l' FiledOCt. l2, 1928llnllllllh.'

IN VEN TOR A TTOREY Patented Nov.' 4, 'i930 UNITED STATES wat.

PATENT? OFFICE EYVIND FINSEN, F ROCHESTER, NEW YORK, ASSIGNOR TO GLEASONWORKS, 0F ROCHESTER, NEW YORK, A CORPORATION OF NEW YORKGEARFG'ENERATING MACHINE Application led October 12, 1928, Serial No.312,173.

The present invention relates to a machine for generating gears andparticularly to a machine for generating bevel gears of the type inwhich the generating roll is elected iii part by gear segments.

The primary purpose of this invention is to provide a machine of thetype described which will be more universal than similar machines ofprevious constructions, in other l.) Words, which will be capable ofcutting a.

greater range of gears than previous machines of the same type. l

A further object of this invention is to provide in a machine ofthecharacter described i; a construction that will insure in the highestdegree a uniform and steady operation of the moving parts avoiding anyslight irregularities in the motion of the machine which might adverselyatleet the tooth finish ob- ;'i tained on the gears generated.

Other objects of the invention will appear hereinafter from thefollowing description and from the recital of the appended claims.

Figure l is a perspective view ot a straight L toothed bevel geargenerating machine constructed according to a preferred embodiment ot'the present invention, parts of the frame being broken away to show moreclearly certain features of the improved construc- :xi tion;

Figure. Q a front elevation of the generating cams and associated partsfor oscillating the cradle;

Figure 3 is a section through the machine C43 and parts shown in Figure2;

Figure 4 is a side elevation of the generating segments and showingparticularly the mounting for the crown gear segment;

Figure 5 is a. view of the crown gear seg- J ment -and its mountingtaken at right angles 5") tion and in plan, respectively, showing analternative form of roller mounting which is particularly advantageouswhen a pinion is being cut on the machine and the rolling motion iseffected in part by a pinion segment.

The presentinvention provides an improvement over the machines ofPatents Nos. 1,660,502 and 1,679,809 and of the copending application ofJames E. Gleason et al., No. 220,785, tiled September 20, 1927, asregards the mechanism for producing the generating roll. The presentinvention is illustrated in connection with a machine for generatingstraight tooth bevel gears but it will be linderstood that it is equallyapplicable to machines for generating curved tooth bevel gears.

In a machine of the type to which the present invention relates, therelative generating roll between tool and blank is produced byoscillating a cradle or carrier on which either the tool or blank ismounted and simultane ously effecting a rota-tion otl the blank on itsaxis through the rolling engagement of a gear segment` to which theblank spindle isconnected, with a gear segment having a relatively fixedrelation to the tool. In most instances, this second segment is mountedon a relatively fixed part of the machine and the Work head or supportis mounted on the cradle and it is in connection with a machine of thisparticular form, a machine in which all t-lie roll is on the work, thatthe present invention is illustrated.

vA machine of the type described has the advantage of essentialsimplicity, requiring a minimum number of operating parts. Early effortsat building machines ot this character, however, were restricted to themanufacture of machines which were intended purely and simply for highproduction work where a machine could be kept busy turning out inquantity the same gear for, with the earliest construction of machinesof this type, it was necessary to change both the Work segment and therelatively fixed segment in order to cut gears of different pitch coneangles and these segments are costly. In an effort to universalize thistype of machine so as to make it economically practical to cut rears ofvarious cone angles on the same mac inc, changes were proposed and madein the nature of the gear segments controlling the roll. Efforts in thisdirection resulted in the invention described in the copendingapplication of James E. Gleason et al., Serial No. 220.785 abovereferred to in which the present applicant is one of the jointinventors. The invention of this prior application provided meanswhereby gears of different dimensions might be produced on the samemachine correctly and with a minimum of tool adjustment by changing theWork segment only. But even with this last named invention, the rangeot' the machine was still limited to the production of either gears orpinions because of the fact that there is a Wide diHei-ence in theamount of roll required to fully generate the profile of a pinion toothfrom that required to fully generate the profile of a gear tooth. Itwould be impossible to fully generate a gear tooth with a rollsufficient only for generating a pinion tooth and to use the same rollfor generating a pinion as would be required to generate a gear would bewasteful in time, uneconomical and, therefore. impractical. Further itthe long roll required for generating a gear were employed in generatinga pinion, there would be a considerable danger of interference betweenthe rolling parts and the stationary parts of the machine because thework head must be adjusted angularly on the cradle closer to the toolsfor generating a pinion than for generating a gear in order to bring thepinion blank into operative relation With the tools. As a result,despite the improvement constituting the invention of application No.220.785. it remained the practice to still use separate machines forcutting gears and pinions.

Through the improvement of the present invention.v it is possible,however, to produce both gears and pinions economically on the samemachine. This is accomplished at the same time without any danger ofinterference between the Work head and the relatively stationary partsof the machine during the generation of either type o gear.

With the present invention, two separate cams are provided foroscillating the cradle. the cam paths of Which aie of widely difierentconformation so that one cam is capable of rolling the cradle through acomparatively large angle as required when generating gears and theother cam is capable of rolling the cradle through a comparatively smallangle only and is used when generating pinions. single roller orfollower is provided engageable selectively With either Cain to transmitmotion trom either cam to the cradle.

lilith the present invention, further, the purpose of obtaininguniversality is tor- Warded as in application No. 220,785 by producingthe blank rotation through a bevel gear segment which is attached to theblank spindle and which has a pitch cone angle less than the pitch coneangle of the blank and a relatively fixed but resiliently mounted crowngear segment. Hence, only the Work segment requires changing for cuttinggears or pinions of different cone angles. The present inventionconstitutes, however, in this regard an improvement over theconstiuction of the prior application mentioned in the mounting of thecrown gear segment, this segment being mounted for pivotal movement.Through this pivotal mount-ing, a uniform steady operation of themachine is insured and at the same time all possibility of interferenceof any of the moving parts with any ot the stationary parts during theroll is completely avoided.

Reference Will now be had to the drawings for a more completeunderstanding of the principles of the present invention. A straighttooth bevel gear generating machine embodying in its construction theimprovements of this invention is shown. 10 indicates the bed or frameof this machine. This bed or frame is provided at one end With anupright portion 12 which serves as a support for the oscillating cradle13 on which the Work head is mounted. The base or frame l0 serves as asupport, also. for the tool carrier 15 which will preferably be mademovable toward and from the Work head in order to withdraw the toolsfrom engagement with the blank for indexing and in order to feed thetools into depth and in order, also, to separate the tool from the Workhead far enough to take ofi' a completed gear and chuck a new blank. Thetool carrier carries tivo tool slides, one of which is to be seen at 16and each of the slides carries a planing tool for cutting the gear toothsurfaces. The means for adjusting the tools and actuating the same andfor actuating the tool carrier may be ot the character described in thepatent to Gleason et al. No. 1,660,502 of February 28, 1928, abovereferred to or of any other suit-able type. It is to be distinctlyunderstood that the present invention is not limited to the use onmachines for producing straight tooth gears as it is usable, also, onmachines of the character described in Patent No. 1,679,809 ot August 7,1928, to Bullock et al. abovei'eferred to and on machines of the. typedc.- scribed in copcnding application No. 220.785 above referred to andon other types of inachines, also, as will be obvious to those skilledin this art.

The work head carries the gear blank (t to be generated. The gear blankmay he secured to the work spindle by means of a draw rod, one end ot'which is seen at 18 (Fig. 1). ln the machine illustrated, the indexingmechanism is ot` the notched-plate tv vpe. The type ot' indexingmechanism to be employed, however, has no relation to the presentinvention and any suitable type of indexing mechanism mar be used on myimproved form of machine.

In the form of indexing mechanism shown, a notched-plate l) is securedto the work spindles. the work spindle is iournaled in a sleeve which isin turn journaled in the work head and the spindle and sleeve areconnected together duringr cuttingr by a loc-king.)y dog, such as shownat '20. which is mounted upon au arm 'il which is secured to the sleeveabove referred to. l`)urin; T cutting, the sleeve and spindle are lockedtogether and for indexing, the sleeve. and spindle are rotatedrelatively to each other. For a more complete description of theoperation ot' the indexing mechanism shown. reference may be had toPatent No. 1.660.502 above referred to.

The means for etl'ecting' the generating roll will be described now.Journaled in the trame of the machine. is a cam shaft 25. Keyed to thisshaft is a large .ca-m 26 provided with a closed track 27. A nut 28serves to hold the cam 2G on the shaft. Secured to the outer face ot thecam 26, asby means of screws :2Q is a second smaller cam 30 of the`peripheral or open type. The periphery of the cam 30 which constitutesits cam pat-h is of a different configuration from the cam track ot thecam "lo and so formed as to transmit to the cradle lf3 an oscillatingmovement through a much smaller angle. in one revolution of the camshaft, than will be transmitted by the cam :2G in one revolution. Thetwo cam paths are formed, however, so as to align at one point, as atthe point 32 indicated in Figure Q.

livotallv mounted upon a stud 34 which is secured to the frame b vsuitable means, as the ,screw 3;?. is an arm 3h. 38 designates aconnectingy rod comprising the short arms 39 and l() which areadjustabhv connected by the turn-buckle 4l. The arm 39 is pivotallyconnected tothe cradle lf3 at 40. The arm 40 has a swivelled connectionthrough the bolt 43 with a block l which is slidably adjustable in aT-slot 45 formed in the tree end of the arm 3o. AMijnstniente of theblock lll to var)v the throw of the connecting rod 38 can be effected bv rotating the screw 4:6 which has a threaded connection with the block#llt and is secured to a plate 4T which is secured to the ym :lo by pinsor screws and which forms one cud wall oll the T-slot l5.

The arm lt formed il'itermediato its` ends with an integral housing 5t)of generally cylindrical shape. Mounted in the housing is a.g-ylindrical member 5l to the outer end ot' which .secured a cam roller52. The Cylindrical member 5l is mounted for axial movement in thehousing 5t) in a direction parallel to the axis ot the cam shaft 25 butis held against rotational movement in the housing b v a ke)v whichengages a suitable slot formed in the housing.n The end of thecylindrical housing 50 opposite to the roller 5'.) is closed h v a plate55 which is secured to the housing` by screws 56. The plate is boredcentrally to receive the stud ot' a screw 57, the threaded portion ofwhich engages a correspondingly threaded opening' tapped into the innerend of the cylindrical member 5l. The screw 5T is' uuthreaded where itpasses through the end plate 55 and is locked against axial movement inthe cud plate by its head 58 and a lock nut. 5S).

A hole. ti() is formed in thc frame or basa- 10 of the machine.' The camroller 52 is adapted to engage selectively either ot the cams 26 or JEU.llvheu the screw 57 is turned to the limit ot its movement in onedircctiou, the cylindrical member 5l will be moved in the housing 50 toengage the roller 5'.) with one of the cams and when the turned to thelimit of its movement in thcl opposite direction. the carrier 5l will bemoved to bringv the roller into engagement with the track of the othercam. Before mov- 'crew 5T is ing the roller from engagement with one camtoenlalement with the other, however, the cam shaft will he rotated tobring the point at. which the two cam paths are in alignment, under theroller so that thev roller will slip readily ott' one cam track onto theother. The hole 6() is so located in the 'frame l0 that. when the rolleris at the point 3;), the head 5h' of the screwi' will be disposedcentrally ot this hole so that the operator ot' the machine can easilyinsert a socket wrench or other suitable tool and turn the screw 5T.

It has been deemed liest to provide a means for locking the cylinder 5lin either ot its limit positions. To thisl end there is mounted in thehousing' 50 at one side thereof. a lsprintf pressed plunger (S2 which isadapted to engage in one or other of t-.hc two holes (i3 formed in theAarrier 5l and corrcspouiiug to the limitI positions ot this carrier.For withdrawingr the plunger (S2 from engage ment with either hole (i2-3to permit movement of the 1ollcr5;..a volte member (il is providedA Thisvolte member 64. is pivotcd between a pair of ears (i5 formed integralwith the hom-'- ing 50. The shorter arm ot the volte member 6l isslotted at its end and engages under thc head G6 ot the sprimgr plunger(3;). lhe longer arm of the yoke -t is bent and biturcacd :is clearlyshown at` (i8 in Figures l and L. 'the furcations extend on either .sideof the head ofthe screw 5T in a posit iou to he engaged by the socketwrench or other tool empio-tml to move the screw 5T before this toolcati hc securely engaged with the head 5S ot this screw wherebyy thevolte tit is rocked about its pivot to withdraw the plunger 6:2 beforethe tool is engaged with the hea d ot the screw so that when the tool isfirmly engaged with the head of the screw the carrier 5l can he moved.All the time that the tool is engaged with the head of the screw, theplungero'. will be held in withdrawn position h v the the work segment.

voke member, but as soon as the carrier 5l has been moved to its newlimit position and the tool has been withdrawn from engagement with thehead of the screw, the coil spring 69 will move the plunger 6:2 intoengagement with the adjacent hole 63 to lock the carrier 51 in this newlimit position.

From the preceding description, it will be seen that on rotation of thecam shaft 25, which may he driven from any suitable source ot' power, anoscillating motion will be imparted to the cradle 13, the angular extentot which will be determined in part by which cam the roller 52 isengaged with and in part b v the position ot the block 44 in the T-slot45 formed in the arm 36.

As has previously been described, the Work spindle on which the gearblank G to be cut is mounted. is journaled in a sleeve which in turn isjournaled in the work head. Provision made for securingr to this sleevea gear segment. the pitch cone angle of which will vary according to thepitch cone angle of the gear to be cut. By suitably' selecting the pitchcone angles of the segment which is secured to the sleeve. gears ofdifferent pitch cone angles can be generated. In the machineillustrated, the gear segment which is secured to the sleeve is adaptedto roll on a relatively stationary gear segment which is mounted upon arelatively fixed part of the machine. Figure l shows the work headadjusted to the proper angle to bring the blank G into operativerelation with the tools and shows a gear segment 70. which is secured totho sleeve in meshing engagement with the relatively .stationary gearsegment 71.

In :wcordance with the principles of copending application No. 220,785above referred to. the work segment will preferably be so selected thatits pitch cone angle is less than the pitch cone angle of the gear to begenerated and the segment 71 will be a crown gear lsegment which isresiliently held in mesh with By selecting the segments in this way. ithas been found that gears ot ditl'erent pitch coneangles can begenerated accurately by simply changing the work segment. the resilientmounting of the crown gear segment permitting of the yielding movementreouired when rolling with work segments ol' dierent pitch cone angles.

One feature ot the present invention is the improved mounting for thecrown gear segment. Secured to the trame 10 of the machine. as by bolts75 is a bracket 7G. Mounted on this bracket 76 tor angular adjustmentthereon about a point coinciding with the apex of the blank is astandard 77. rThis standard is guided in its angular adiustment b v alug 78 which engages in a T-slot 79 formed in the upper face of thebracket 76 and it can be secured in any adjusted position by means ofthe bolts 8O which engagel in the T-slot 79 and a bolt 81 which engagesin a T-slot concentric therewith. The crown gear segment 71 is pivotallymounted on the standard 77 being secured by means of screws 84 to an arm85 which is pivotally mounted 0n the standard 77 by means of a bolt orstud 86. The axis of the bolt or stud 86 is inclined, in the machineshown, to a horizontal plane. In generating bevel gears, the axes of theblank spindle and of the cradle are angularly disposed to each other andintersecting; they licl in the same plane. The axis of the stud 86 isobliquely disposed to this plane which here is horizontal and passesthrough the apex of the basic crown gear, represented by the tools. towhich the gear to be cut is generated conjugate. the pivotal axis of thecrown gear segment, a. correct rolling motion is imparted to the blankto correctly generate the tooth profiles. The arm 85 is guided in itspivotal movement about the axis of the stud 86 by means of a gib 88,which is secured to the arm 85 as by means of screws 89 and whichengages an arcuate flange or track 90 formed on the standard 77concentric of the axis of the stud 86.

As will be. clearly seen, as the cradle 13` oscillates on its axis, thegear segment 70 will roll on the pivotally mounted crown gear segment 71thus rotating the. sleeve. to which the gear segment 7 0 is connected.on its axis and since the sleeve is connected to the, Work spindlethrough the index mech anism, during cutting. the work spindle will berotated on its axis. The combined rotation of the work spindle. and theoscillation of the cradle impart to the work a rolling movement relativeto the tools to generate the tooth profiles.

To maintain the crown gear segment 71 in mesh with the gear segment 7 0as they roll together and to permit of the yielding movement required toenable the crown gear segment to roll with gear segments of any pitchcone angle and impart to the work the proper rolling motion. a resilientmeans is provided for constantly urging the crown gear segment towardthe work segment. This means will now be described.

Two separate constructions are shown for holding the work segment andcrown gear segment in mesh. one construction. shown in Figures 4. 5 and6 is particularly applicable where gears are being cut and afgearsegment is being used and the other construction is particularlyapplicable where pinions are being cut and a pinion segment is beingused. I shall refer to the construction shown in Figures 4. 5 and 6tirst. Each of the segments 7l and 70 are provided with a groove. 94 and95, respectively, arranged parallel to their respective pitch surfaces.These grooves receive. respectively. a pair of rollers 96 and 97 whichare adapted to travel in the grooves as the segments roll on each other.

Through this disposition of svedese The rollers 96 and 97 are secured,respectively, to a pair ot' arms 98 and 99 which are pivotally mountedon a stud or bolt 100 which is secured in a bracket 101 which isadjustably secured to the upper tace of the cradle 13. The arms 98 and99 are, respectively, of sub stantially T-shape, the legs of the Ts arepivoted on the stud 100 and one arm of each T carries a roller 95 or 96.The other arms of the T`s are provided with a cup shaped recess andbetween theseis i terposed a coiled spring 103. This coil spring isheavy enough io maintain the two segments in mesh as they roll together.The bracket 101 is secured to the upper face ot the cradle by means of aT-bolt 104 which engages in the T-groove 102 formed in the face oi' thecradle. A lug may be provided on the bracket 101 for centering it duringits adjustment, this lug entering the slot 10:2. 1t desired, also, thebracket may be provided with a flange, as clearly shown in Figureextending over the side ot' the face plate of the cradle.

Where pinions are to be out, usually the length ot the arm carrying thepinion segment is so short that a groove extending parallel io the pitchsurface of the segment could not be provided in this arm. Consequentlywhere the segment connected to the Work is a pinion segment, 1 prefer touse a resilient holding device such as shown in Figs. 7 and 8. Here. 71again designates the crown gear segment while T is the pinion segment,the crown gear segment is grooved as before at 95 to receive a roller105 which is mounted on a lever arm 106 that is pivotally mountedintermediate its length on the stud 107 which is pivotally mounted upona bracket 108 that can be secured to the face plate of the cradle. Theend of the arm 100 opposite to that carrying the roller 105 is enlargedand provided with a cup shaped recess 110. rll`he bracket S formedintegral with it an arm 111 which has. also. an enlarged outer endformed with a cupped shape recess 112. interposed between the two arms100 and 111 and seated in the cup shaped recesses 110 :ind 112 is acoiled spring 114. The arm 106 is limited in its pivotal movement aboutthe stud 107 under actuation of the spring 114 by means ot' a bolt 115which is threaded int-o the arm 111 and passes through a slot 116 formedin the arm 100 and which carries a nut 117 which serves to limit theoutward movement of the arm 106. rlfhe spring 114 pressing against theouter arm of the lever 106 serves to constantly urge the roller 105against the front wall of the groove 95 formed in the crown gear segmentT1 to maintain this segment 71 constantly in mesh with the pinionsegment 70. The bracket 108 can be secured in any adjusted position onthe cradle by means of bolts 119 which are mounted in the cradle andpass through suitable slots formed in the bracket. A. tongue or lug 120on the bracket 108 engaging in a slot formed in the periphery of thecradle face plate serves to guide the bracket 108 in its adjustn'icnt.By means 0f the spring pressed rollers 96 and 97 or the spring pressedroller 105. the crown gear segment can be maintained constantly in meshwith the bevel gear or pinion segment which is secured to the sleeve ot'the Work head. The pivotal mounting of the crown gear segment enablesthis segment to move freely without binding as required.

The operation of the machine constructed according to the presentinvention will be clear from the preceding description and may bebriefly summed up here. The standard 7T can be adjusted on the bracket70 to obtain any desired position of the crown gear segment at anypredetermined point in the roll. Preferably, the crown gear segment willbe adjusted so that at the bottom or top of the roll it is in a verticalposition. The bracket 101 or 108, as the case may be depending uponwhether a gear or a pinion segment is secured to the sleeve in which thework spindie is mounted, will then be adjusted to secure the propertension on the crown gear segment. The work segment T0 will be selected,preferably, as already described, and the work head and tool can beadjusted into operative relation by any usual suitable means. The closedcam 26 will be used where a gear is to be generated because this impartsto the cradle an oscillatory movement through a large angle as requiredin generating gears. The smaller cam 30 will be used for generatingpinions. ln generating pinions, the work head is close to the tools. Ingenerating gears. however, the work head extends at a coiisiderableangle to the tool head and a cam. such as 26 having a closed pat-h is apractical advantage because ot' the manner in which the weight orn thework head is distributed when positioned for cutting a gear.

The amount of roll of the cradle in either case depends not onlv on theform of the cam path but also ou the setting of the block 11 by means ofthe screw C as this` governs the throw of the connecting rod Byadjusting the turn buckle 11, the ratio of angular movement above centerand below center can be controlled. Vv'hen the roller 52 has beenpositioned in engagen'ient with the desired cam path by moving theroller carrier 51 by rotating the screw 57 and the yoke 61 has beenreleased to permit the plunger 62 to lock the roller carrier ineitherposition or its adjustment and when the. 'arious other adjustmentsnecessary have been made. the machine can be put in operation. As thecam shaft rotates.

the cradle 13 will be oscillated and the oscillation ot' the cradle willcause the work segment to roll on the crown gear segment which is heldresiliently in engagement with the work segment thereby imparting arotary movement to the sleeve, and during cutting,

to the work spindle. IVhen a gear surface has been generated, the sleeveand work s indie can be disconnected and the work spin le indexed andagain locked to the sleeve for generating the next tooth surface.

IVhile the present invention has been described in connection with amachine for generating bevel gears, it will be understood that theimprovements ofthe present invention are applicable to other types ofgear generating machines, also, as, for instance, to machines forgenerating h vpoid gears. Moreover, while the gear segment arms and 70have been shown as made in one piece, it will be understood that ifdesired, these arms may each be made in two parts so that the length ot'the arms can be adjusted. Through this adjustment, the cone surface ofthe work segment while rolling on the pitch surface of the crown gear ischangeable. so that within limits, one work segment can be used ingenerating different gears or pinions, as the case may be.

In general, it may be said that while a preferred embodiment of theinvention has been described, the invention is capable of variousfurther modifications and uses and that this application is intended tocover any variations, uses, or adaptations of the invention, following,in general, the principles of the invention and including suchdepartures from the present disclosure as come within known or customarypractise 'in the gear art and as may be applied to the essentialjfeatures hereinbetore set forth and as fall within the scope of theinvention or the limits ci' the appended claims.

Having thus described my invention, what I claim is:

l. In a machine for generating gears, a work spindle. a tool, and meansfor producing a relative rolling movement between the work spindle andtool including a gear segment connected to the work spindle, a pivotallymounted gear segment. on which the first segment is adapted to rollhaving a fixed relation to the tool, said pivotally mounted segmentbeing capable of angular motion about its pivot during the rollingmovement, and means for resiliently holding the two segments in mesh.

2. In a machine for generating gears, a work spindle, a tool and meansfor producing a relative rolling motion between the Work spindle andtool including a gear segment connected to the work spindle, a secondgear segment pivotally mounted on a relatively fixed part of the machineon which the first segment adapted to roll, said second segment beingcapable of angular motion about its pivot during the rolling movement,and means tor resiliently holding the two segments in mesh.

3. In a machine for generating gears, a work spindle, a tool, and meansfor producing a relative rolling movement between the work spindle andtool including a gear segment connected to the work spindle, a secondgear segment mounted for rocking movement on a relatively fixed part ofthe machine on which the first segment is adapted to roll, and means forresiliently holding the two segments in mesh.

4. In a gea-r generating machine, a tool, a Work support, anoscillatable cradle upon which the work support is mounted, a workspindle journaled in the work support, a gear segment connected to thework spindle, a second gear segment, on which the first segment isadapted to roll, pivotally mounted on a relatively fixed part of themachine, said second segment being capable of motion about its pivotduring the rolling movement, means for resiliently holding the twosegments in mesh, means for oscillating the cradle and means foractuating the tool.

5. In a gear generating machine, a tool, a work support, an oscillatablecradle on which said work support mounted, a work spindle ,v

disposed to the axis of the cradle, a gear segment connected to the workspindle, a second gear segment pivotally mounted on a relatively iixedpart of the. machine for angular movement about an axis obliquelydisposed to a plane containing the axes ot' the cradle and work spindle,means for resiliently holding the two segments in mesh, means foroscillating the cradle. and means for actuating the tool. i

7. In a gear generating machine, a frame, a tool, a work support, acradle, upon which the work support is mounted, oscillatablv mounted inthe frame for movement about a horizontal axis, a work spindle jonrnaledin the work support for movement about a horizontal axis angularlydisposed to the axis of the cradle, a gear segment connected to the Workspindle, a second gear segment, on which the first segment is adapted toroll, pivotally mounted on a relatively fixed part of the machine forangular movement about an axis obliquelv disposed to a horizontal plane,means or resiliently holding the two segments in mesh, means foroscillating the cradle and means for actuating the tool.

8. In a gear generating machine, a tool, a Work support, anoscillartablc cradle upon which thework support is mounted, a workspindle journaled in the work support, a gear fil segment mounted on thework spindle, a second gear segment, on which the first segment isadapted to roll, pivotally mounted on a relatively fixed part ot themachine, said second segment being provided with a groove extendingparallel to its pitch surface, a roller pivotally mounted on arelatively fixed part ot the machine and adapted to travel in saidgroove as the segments roll together and resilient means resistingpivotal movement of said roller on its support to thereby resilientlyhold the tivo segments in mesh.

9. ln a gear generating machine, a tool, a work support. an oscillatahlecradle upon which the work support is mounted, a work spindle journaledin the work support, a gear segment secured to the work spindle, asecond gear segment, on which the first segment is adapted to roll,pivotally mounted on a relativelyy ixed part of the machine, each ofsaid segments being provided With a groove extending parallel to theirrespective pitch surfaces, a pair of rollers pivotally mounted on arelatively fixed support and adapted to travel insaid grooves as thesegments roll together. and resilient means resisting pivotal movementof said rollers on their support to resiliently hold the two segments inmesh, means for oscillating the cradle, and means for actuating thetools.

10. n a gear generating machine, a Work support, a tool support, acradle upon which one of said supports is mounted, a Work spindlejournaled in the work support, a. toothed memher connected to the workspindle, atoothed member having a fixed relation to the tool upon whichthe first named member rolls, and means for imparting an oscillatorymotion to the cradle to produce a relative rolling motion between thetool and blank comprising a pair of cams, a roller engageahleselectively with either ot' said cams and means operatively connectingthe roller to said cradle to oscillate the cradle on rotation of the camwith which the roller is engaged, said cams having different contours toimpart to the cradle selectively movements of diii'erent angular'extent.

11. ln a gear generating machine, a frame, a work support. a toolsupport, a cradle oscillatahly mounted on the frame and upon which oneof said supports is mounted, a work spindle journaled in the worksupport, a gear segment connected to the Work spin ille. a gear segmenthaving a xed relation to the tool upon which the first segment rolls, acam shaft jonrnaled in the trame` a pair of cams secured to the camshaft, means tor oscillating the cradle on rotation of said cam shaftincluding a roller operatively connected to the cradle and selectivelyengagealole with either cam, said cams having di'erently formed campaths to oscillate the cradle selectively through different sized arcs,the paths of said cams being so formed as to align with each other atone point, and means for moving the roller from engagement with one faminto engagement with the other when the roller is at the point ofalignment of the cam paths.

12. In a gear generating machine, a frame, a work support, a toolsupport, a cradle oscillatably mounted on the frame and upon which oneof said .supports is mounted, a Work spindle journaled in the worksupport, a gear segment connected to the work spindle, a gear segment,having a xed relation to the tool, upon which the rst segment rolls, acam shaftl journaled in the frame, a pair ot cams secured to the camshaft, means for oscillating the cradle on rotation of said cam shaftincluding a roller operatively connected with the cradle and selectivelyengageable with either cam, said cams having differently formed campaths to oscillate the cradle selectively through different sized arcs,the paths of said cams being so formed as to align with each other atone point, means for moving the roller from engagement with one cam intoengagement with the other when the roller is at the point of alignn'xentof the cam paths, and means for locking the roller` in either positionof its adjustment and means for automatically unlocking the lockingmeans when a suitable tool is engaged Wit-h the means for moving theroller.

13. ln a gear generating machine, a frame, a Work support, a toolsupport, a cradle oscillatahly mounted on the frame and upon which oneot said supports is mounted. a Work Spindle journaled in the worksupport, a gear segment connected to the work spindie, a gear segment,having a fixed relation to the tool, upon Which the first segment rolls,a cam shaft journaled in the frame, a pair of cams secured to the camshaft, the larger of which is a closed cam and the smaller ot' which isan open cam and the paths of which are so formed as to align with eachother at one. point, means for oscillating the cradle on rotation ofsaid cam shaft including a roller operatively comacted with the cradleand selectively engageahlc with either cam.

14. In a gear generating machine, a trame, a Work support, a toolsupport, a. cradle os cillatably mounted on the trame and on which oneof said supports is mounted, a work spindle journaled in the Worksupport, a gear segment connected to the work spindle. a. gearsegmenthaving a fixed relation to the tool upon which the first segmentrolls. a cam shaft journaled in the frame, a pair of camsl secured tothe cam shaft, the larger of which is a closed cam and the smaller ofwhich is an open cam and the paths ot which are so formed as to lalignwith each other at one point, means for oscillating the cradle onrotation of the cam shaft including a roller operatively connected withthe cradle and selectively engageable with either cam, a carlll() 8meesso rier to which the, roller is secured, a screw for moving theroller-carrier in a direction parallel to the axis of the cam shaft fromengagement with one cam into engagement with the other when the rolleris at the point of alignment of the cam paths, a spring-pressed plungeradapted to engage with one or other of two holes tormed in theroller-carrier to secure the roller in either position of its adjustmentand a pivoted yoke member, one arm of which is connected with saidplunger and the other arm otl which extends to a position relative tothe head of said screw such that before a suitable tool can be engagedwith the head of the screw to rotate the Same to move the roller, thetool must engage the voke and withdraw the plunger from lockingposition.

l5. In a gear generating machine, a tool, a work support, a cradle uponwhich the work support is mounted, a work spindle journaled in the worksupport, a bevel gear segment. having a pitch cone angle less than thatot' the gear to he cut, connected to the work spindle. a crown gearsegment, on which the first segment rolls. pivotally mounted on arelatively fixed part of the machine, and means tor resiliently holdingthe two segments in mesh.

1G. In a gear generating machine, a frame, a tool mounted on the frame,a work support, a cradle oscillatahly mounted on the frame and uponwhich the work support is mounted, a work spindle journaled in the worksupport. a gear segment connected to the work spindle, a second gearsegment, on which the first segment rolls, pivotally mounted on arelatively fixed part of the machine, means for resiliently holding thetwo segments in mesh. a cani shaft journaled in the frame, a pair ot'cams secured to the cani shaft, means i'or oscillating the cradle onrotation of said cam shaft includingr a roller operatively connectedwith the cradle and selectively engagcable with either cani. said camshaving (lifi'crcntly formed cam paths to oscillate the cradle throughdifferent sized arcs, the paths of said cams being so formed as to alignwith each other at one point, and means for moving the roller fromengagement with one cam into engagement with the other when the rolleris at the point of alignment of the cam paths.

1T. In a gear generating machine, a trame, a tool mounted on the frame.a work support, a cradle oscillatably mounted on the frame and uponwhich the work support is mounted. a work spindle journaled in the worksupport. a gear segment connected to the work spindle, a second gearsegment. on which the first segment rolls, pivotally mounted on arelativelyv tixcd part ot' the machine, means for resiliently holdingthe two segments in meslna cain shaft journaled in the frame, a pair ot'cams secured to the cam shaft, the

larger of which is a closed cam and the smaller of which is an open camand the paths of which are so formed as to align with each other at onepoint, means for oscillating the cradle on rotation of the cam shaftincluding an arm pivotally mounted at one end on the frame, anadjustable connecting rod pivot-ally connected at one end ot the cradleand pivotally connected atI its opposite end to the arm at the end ofsaid arm remote from its pivotal connection with the iframe, and aroller movably mounted on the arm at a point intermediate its ends forselective enga gement with either cam when the roller is at the point ofalignment of the cani paths.

18. In a gear generating machine, a frame, a tool mounted on. the frame,a work support, a. cradle oscillatably mounted on the frame and uponwhich the work support is mounted, a work spindle journaled in the worksupport. a bevel gear segment connected to the work spindle, a crowngear segment, on which the first segment rolls.vpivotally mounted on arelatively fixed part of the machine, means for resiliently holding thetwosegments in engagement, a. cam shaft j ournaled in the trame, a pairof cams secured to the cani shaft having cam paths so formed as toselectively oscillate the cradle through diiierent sized arcs, saidpaths being so formed as to align with each other at one point, andmeans for oscillating the cradle on rotation of the cam shaft includinga roller operatively connected with the cradle and movable selectivelyinto engagement with either cani.

19. In a gear generating machine. a work support, a stool support, acradle upon which one of said supports is mounted, a work spindlejournaled in the work support` a gear segment connected to the. workspindle` a second gear segment, having a tixed relation to the tool,upon which the iirst segment is rolled, a cam shaft journaled in thetrame. a pair ot' cams secured to the cam shaft. the larger oi which isa closed cam and the smaller oi which is an open cam and the paths ofwhich are so formed as to align with each other at one point, an armpivotally connected at one end to the frame` an adjustable connectingrod pivotallyv connected to the cradle atone end and at its opposite endpivotally connected to the free end ot' said arm, said arm beingprovided with a housing intermediate. its ends, a member car rying aroller engageable with said cam movable in said housing in a directionparallel to the cam shaft, means for moving the roller carrier in thehousing when the roller is at the point of alignment of the two cams andmeans for releasabljr securing said roller carrier in either position otits adjustment.

20. ln a gear generating machine, a tool, a work support, anoscillatable cradle upon which the Work support is mounted, a work llospindle journale in the Work support, a bevel gear segment, having epitch cone angle less than the pitch cone angle o the gear to be cut,secured to the Work spindle, a crown gear segment, with `which the rstsegment is adapted to roll, pivotally mounted at one end on a relativelyxed 'peet of the machine, means for resiliently holing the two segmentsin mesh, and means for oscillating the cradle including :L pair of camshaving cam paths so formed as to oscllate the cradle selectively throughdifeent sized arcs, said paths being so formed, also, as to align witheach other et one point, and e roller operatively connected with thecradle and movable selectively from enga ement with one cam intoengagement Wit the* other when the roller is at the point of alignmentof the two cam paths.

EYVND FllNSEN.

